In natural ecosystems, nobody beats the apex predator directly, and nobody beats the hyperspecialized niche critter at their own game. The new species has some advantage that’s different than what is there.

If a humanoid robot is slower dumber human that is expensive, requires power, can’t get wet, falls over, and doesn’t understand stairs. Is not sleeping and being radiation tolerant enough of an advantage to be worth it?

They already are, the problem with humanoid robots is that people think that adding legs to the robot will somehow fundamentally make it more intelligent.

People see a robot arm attached to a stationary platform and understand it requires integration work to perform a single task.

But when those same people see a humanoid robot, they think they can just talk to it like a real human and it will do what you told it to do.

They don't think about the fact that the humanoid robot has to be programmed exactly the same way the stationary robot arm has to be programmed and that programming the legs in addition to the arms is a much more challenging problem.